It is believed that to consume the flesh of a mermaid, means that you will never show signs of age, and live forever. However, many cannot handle its taste and become demons for eternity. Towa is a woman whose thirst for this flesh consumes her, as she was made only partially immortal by drinking the blood of a mermaid years ago. Unable to cast her demons aside, she destroys everything in her path on a search for this legend.
Suzuko and Shu are siblings who live in an undetermined part of Tokyo. While walking together one day, an explosion suddenly occurs, and Suzuko awakens in an unfamiliar place: the past. The time is during Japan's civil war, and the faces are anything but friendly. With the help of newly-met Shukumaru, Suzuko must unravel the mystery of her disappearance and discover the connection between these two worlds, while trying to figure out how she can return to her own time and place.
Legend says that if the flesh of a mermaid is consumed, the body becomes immortal. However, with the small chance of immortality comes a high chance of being poisoned, morphing and mutating into a monster beyond comprehension. Yuta is a wanderer: one of the few who has eaten the flesh and survived, and lived to tell about it -- for 500 years. By chance, Yuta meets a young woman named Mana who also shares the same fate, and together, they wander the land, searching for a mermaid who can free them from their immortal lives.
Following in the footsteps of Mermaid Forest (another OVA by Rumiko Takahashi), Yuta and Mana are back, and have travelled to a new city for work and rest. By chance, they meet Masato: a young boy whose mother is known to have come back from the dead. The pair discover that Masato's household contains dark secrets, which may end up costing them their lives!
At Count D's pet shop, you can acquire any form of animal, from an ordinary canary, to more.. "exotic" creatures. Made to sign a contract before purchase, Count D claims no "responsibility for actions incurred" if the purchaser does not follow its instructions completely, as results can be fatal. Patrons of this shop are able to get the rarest of creatures, but often, their purchases are coupled with demons from their past that won't go away easily.